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Self-consistent strong plasma screening around light nuclei is implemented in the Big Bang nucleosynthesis (BBN) epoch to determine the short-range screening potential, e ϕ (r)/ T ≥ 1, relevant for thermonuclear reactions. We numerically solve the nonlinear Poisson–Boltzmann equation incorporating Fermi–Dirac statistics, adopting a generalized screening mass to find the electric potential in the cosmic BBN electron–positron plasma for finite-sized α particles (4He++) as an example. Although the plasma follows Boltzmann statistics at large distances, Fermi–Dirac statistics is necessary when work performed by ions on electrons is comparable to their rest-mass energy. While self-consistent strong screening effects are generally minor owing to the high BBN temperatures, they can enhance the fusion rates of high- Z (Z > 2) elements while leaving fusion rates of lower- Z (Z ≤ 2) elements relatively unaffected. Our results also reveal a pronounced spatial dependence of the self-consistent strong screening potential near the nuclear surface. These findings about the electron–positron plasma's role refine BBN theory predictions and offer broader applications for studying weakly coupled plasmas in diverse cosmic and laboratory settings. [ABSTRACT FROM AUTHOR]

The r-process is one of the processes that produces heavy elements in the Universe. One of its possible astrophysical sites is the neutron star–black hole (NS-BH) merger. We first show that the neutrons can degenerate before and during the r-process in these mergers. Previous studies assumed neutrons were non-degenerate and the related rates were calculated under Maxwell–Boltzmann approximations. Hence, we corrected the related rates with neutron degeneracy put in the network code and calculated with the trajectories of NS-BH mergers. We show that there are differences in the nuclei distributions. The heating rates and the temperature at most can be two times larger. The change in heating rates and temperature can affect the light curves of the kilonovae. However, this has little effect on the final abundances. [ABSTRACT FROM AUTHOR]

This Resource Letter provides a guide to the literature on the field of nuclear astrophysics, and particularly the origin of the elements. Nuclear astrophysics is a multidisciplinary field that aims at understanding where everything we see around us comes from and how it came to be. Astronomical observations, astrophysics modeling, and nuclear physics experiment and theory come together to answer important questions like: Where and how are the elements created? How do stars evolve? What drives the different types of stellar explosions? What is left behind after the cataclysmic death of a star? This Resource Letter presents our current understanding of the origin of the various chemical elements, together with modern research and new developments in the field, with a particular focus on the measurement of nuclear properties for astrophysical applications. Editor's Note: For many years the source of the energy in stars was a mystery since conventional explanations (gravity and chemical reactions) yielded stellar lifetimes that were too short. With the development of nuclear physics and the interdisciplinary field of nuclear astrophysics, not only was this mystery solved, but others, like the production of elements heavier than helium, were as well. This Resource Letter describes resources that provide a guide to the field of nuclear astrophysics and the origin of the elements. [ABSTRACT FROM AUTHOR]

Research on radioactive ion beams produced with in-flight separation of relativistic beams has advanced significantly over the past decades, with contributions to nuclear physics, nuclear astrophysics, atomic physics, and other fields. Central to these advancements are improved production, separation, and identification methods.The FRS Ion Catcher at GSI/FAIRexemplifies these technological advancements. The system facilitates high-precision experiments by efficiently stopping and extracting exotic nuclei as ions and making these available at thermal energies. High-energy synchrotron beams enhance the system's capabilities, enabling unique experimental techniques such as multi-step reactions, mean range bunching, and optimized stopping, as well as novel measurement methods for observables such as beta-delayed neutron emission probabilities. The FRS Ion Catcher has already contributed to various scientific fields, and the future with the Super-FRS at FAIR promises to extend research to even more exotic nuclei and new applications. [ABSTRACT FROM AUTHOR]

The field of nuclear science has considerably advanced since its beginning just over a century ago. Today, the science of rare isotopes is on the cusp of a new era with theoretical and computing advances complementing experimental capabilities at new facilities internationally. In this article we present a vision for the science of rare isotope beams (RIBs). We do not attempt to cover the full breadth of the field; rather, we provide a perspective and address a selection of topics that reflect our own interests and expertise. We focus in particular on systems near the drip lines, where one often finds nuclei that are referred to as exotic and where the role of the nuclear continuum is only just starting to be explored. An important aspect of this article is its attempt to highlight the crucial connections between nuclear structure and the nuclear reactions required to fully interpret and leverage the rich data to be collected in the next years at RIB facilities. Further, we connect the efforts in structure and reactions to key questions of nuclear astrophysics. [ABSTRACT FROM AUTHOR]

A thorough understanding of nuclear reaction rates at low energies is essential for improving our understanding of energy generation in stars and primordial and stellar nucleosynthesis. At low energies, fusion reactions between charged particles are strongly suppressed by the presence of the Coulomb barrier, which classically inhibits the penetration of one nucleus into another. The barrier penetration causes the cross section to have a steep energy dependence at low energies, making cross section measurements very challenging. Furthermore, little is known about the impact of surrounding electrons in stellar plasmas that are currently beyond the reach of experiments. As a result, measuring the bare cross sections as accurately as possible is essential. Reaction rate measurements at very low energies have been made possible in recent years by the development of high-current low-energy accelerators as well as enhanced target and detection methods. Nevertheless, the presence of atomic electrons, which alter the Coulomb barrier by screening the nuclear charge and increase the cross section at low energies compared to the case of bare nuclei, complicates these observations. A review of the experimental and corresponding theoretical work on laboratory electron screening performed so far will be presented. [ABSTRACT FROM AUTHOR]

A thorough understanding of nuclear reaction rates at low energies is essential for improving our understanding of energy generation in stars and primordial and stellar nucleosynthesis. At low energies, fusion reactions between charged particles are strongly suppressed by the presence of the Coulomb barrier, which classically inhibits the penetration of one nucleus into another. The barrier penetration causes the cross section to have a steep energy dependence at low energies, making cross section measurements very challenging. Furthermore, little is known about the impact of surrounding electrons in stellar plasmas that are currently beyond the reach of experiments. As a result, measuring the bare cross sections as accurately as possible is essential. Reaction rate measurements at very low energies have been made possible in recent years by the development of high-current low-energy accelerators as well as enhanced target and detection methods. Nevertheless, the presence of atomic electrons, which alter the Coulomb barrier by screening the nuclear charge and increase the cross section at low energies compared to the case of bare nuclei, complicates these observations. A review of the experimental and corresponding theoretical work on laboratory electron screening performed so far will be presented.

The JUNA (Jinping Underground Nuclear Astrophysics) platform has the facility with the world’s most intense beams, and provides a crucial opportunity for China to strive for a leading international position in nuclear astrophysics. The first phase of JUNA’s experiments has demonstrated a promising prospect for accurately measuring nuclear astrophysical reactions in underground laboratories. The windowless gas target is a critical component for directly measuring low-energy nuclear astrophysical reactions involving specific isotopes, thereby effectively expanding the scope of deep-underground experiments. Windowless gas targets have been employed in studies of low-energy nuclear reactions in several international laboratories. Represented by the work of Gran Sasso group from Italy, many achievements have been made in nuclear astrophysics research on windowless gas target equipment, including those on Big Bang nucleosynthesis and solar neutrino physics. However, these studies have focused on experiments with relatively low beam intensities. To meet the high-power, high-intensity beam requirements of the JUNA experiment, a dedicated gas target design is needed. In this work, a gas target device that can be used for high intensity beams was designed. Through modeling with ANSYS Fluent and COMSOL software, the feasibility of a multi-stage differential structure was validated. According to the simulation results, it is possible to achieve a total gradient decrease of about 6 orders of magnitude in gas pressure from the target chamber to the accelerator end. This indicates that the current gas target setup is sufficient for our future nuclear reaction measurement experiments. In addition, the heating effect proves to be important for gas target experiment. On one hand, when the beam passes through the gas target, some energy will be deposited, then the target density (i.e. target thickness) near the beam will correspondingly decrease. In nuclear physics experiments, precise measurement of target thickness is an important step in extracting key physical quantities (such as reaction cross-section). Therefore, systematic research is needed on the target thickness changes induced by beam to guide our future experimental set up. On the other hand, due to the possible changes in charge state when the beam passes through a gas target, which may not be detected by current measurement devices (such as Faraday cup), it is necessary to develop methods for normalizing the beam intensity that is insensitive to charge. The calorimeter is an optional solution. The response of calorimeter to thermal power input needs to be carefully studied to guide the future design of calorimeter. Both the beam induced heating effects on target thickness and thermal response of the calorimeter have been investigated by simulation. A design optimization for windowless gas target experiments has been proposed, which can effectively alleviate the beam heating effect and improve the accuracy of calorimeter measurement of beam intensity, providing a reliable foundation for the development of JUNA’s deep-underground experimental research in the future.

This article discusses the field of nuclear physics and its various applications and frontiers. It highlights the importance of collaboration between theory and experiment in making breakthroughs in the field. The article includes contributions from researchers in different subfields of nuclear physics, such as nuclear structure, reactions, dynamics, hadron physics, nuclear astrophysics, and neutrino physics. It also discusses the use of different methodologies, including Monte Carlo approaches and ab initio methods. The article concludes by mentioning upcoming facilities and future opportunities for nuclear physics research. [Extracted from the article]

With current and planned gravitational-wave (GW) observing runs, coincident multimessenger timing of resonant shattering flares (RSFs) and GWs may soon allow for neutron star (NS) asteroseismology to be used to constrain the nuclear symmetry energy, an important property of fundamental nuclear physics that influences the composition and equation of state of NSs. In this work, we examine the effects of combining multiple RSF detections on these symmetry energy constraints, and consider how realistic uncertainties in the masses of the progenitor NSs may weaken them. We show that the detection of subsequent multimessenger events has the potential to substantially improve constraints beyond those obtained from the first, and that this improvement is insensitive to the mass of the NSs that produce the RSFs and its uncertainty. This sets these asteroseismic constraints apart from bulk NS properties such as radius, for which the NS mass is highly important, meaning that any multimessenger RSF and GW events can equally improve our knowledge of fundamental physics. [ABSTRACT FROM AUTHOR]

The Facility for Rare Isotope Beams (FRIB) at Michigan State University is a user facility that supports a global community of scientists in studying rare isotopes. It offers opportunities in nuclear structure and reactions, astrophysics, and physics beyond the standard model. FRIB also provides research quantities of rare isotopes for medical diagnostics and material science. The facility has a range of scientific instruments and is expanding its capabilities with the addition of the High Rigidity Spectrometer (HRS) and an energy upgrade to the linac. The article highlights various instruments and technologies used at FRIB, as well as the development of new technologies that have potential applications in other industries. [Extracted from the article]

The article discusses the n_TOF facility at CERN, which is a research facility designed for studying neutron-induced nuclear reactions. The facility uses a pulsed white neutron source and has three experimental areas where reactions are studied. The article highlights the importance of the neutron source intensity and energy distribution, the repetition rate of neutron-generating pulses, the time resolution of the neutron beam, and the background conditions for conducting accurate experiments. The facility's core program focuses on measuring neutron-induced reaction cross-sections for various applications, including nuclear astrophysics and advanced nuclear technologies. The article also mentions the facility's continuous upgrades and improvements, as well as the collaborative nature of the experiments conducted at n_TOF. [Extracted from the article]

Fluorine is one of the most interesting elements in nuclear astrophysics. Its abundance can provide important hints to constrain the stellar models since fluorine production and destruction are strictly connected to the physical conditions inside the stars. The F 19 (p,α)16O reaction is one of the fluorine burning processes and the correction evaluation of its reaction rate is of pivotal importance to evaluate the fluorine abundance. Moreover, the F 19 (p,α)16O reaction rate can have an impact for the production of calcium in the first-generation of Population III stars. Here, we present the AsFiN collaboration efforts to the study of the F 19 (p, α)16O reaction by means of direct and indirect measurements. On the direct measurements side, an experimental campaign aimed to the measurement of the F 19 (p, α 0 , π )16O reaction is ongoing, taking advantage of the new versatile arrays of silicon strip detectors, LHASA and ELISSA. Moreover, the Trojan Horse Method (THM) was used to determine the F 19 (p, α 0 )16O reaction S(E)-factor in the energy range of astrophysical interest ( E c m ≈ 0–1 MeV), showing, for the first time, the presence of resonant structures within the astrophysical energy range. THM has been also applied for the study of the F 19 (p, α π )16O reaction; data analysis is ongoing. [ABSTRACT FROM AUTHOR]

1. This study focuses on the theoretical and computational determination of the activity of N-15 produced through the 12C(α, p)15N nuclear reaction. The investigation involves the use of alpha particles (α) bombarding carbon- 12 nuclei, resulting in the formation of nitrogen-15 (15N) through proton (p) emission. 2. The calculation methodology encompasses quantum mechanical models and nuclear reaction theory to predict the cross-sections governing the 12C(α, p)N15 reaction at various incident alpha particle energies. Utilizing these cross-sections, the reaction rates are computed, and subsequently, the activity of the produced N-15 is estimated. 3. The impact of reaction parameters such as energy, angular momentum, and nuclear structure on the reaction dynamics is explored. In this research, SRIM and MATLAB programs were used to calculate the Cross section for alpha and carbon-12 interaction, simulate the account yield of 15N, and predict the distribution of N-15 activity. The results of this study provide valuable insights into the fundamental processes governing the 12C(α, p)15N reaction, aiding in the understanding of nucleosynthesis pathways in astrophysical environments and contributing to the development of nuclear models. The calculated N-15 activity serves as a crucial parameter for applications in fields such as nuclear astrophysics, nuclear medicine, and isotope production for various scientific and industrial purposes. [ABSTRACT FROM AUTHOR]

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The study of nuclear isomer properties and the isomer applications is a current research focus of nuclear physics and nuclear astrophysics. Theoretical description of nuclear isomers, the surrounding states, and the interplay of them becomes an important issue. In this article, we present the projected shell model method for describing excited nuclear states in general, and for treating K-isomers in particular. With some examples, we emphasize how to apply the modern nuclear many-body technique to calculate K-isomers and normal excited states on an equal footing. [ABSTRACT FROM AUTHOR]

Quantum tunnelling plays a crucial role in heavy-ion fusion reactions at sub-barrier energies, especially in the context of nuclear physics and astrophysics. The nuclear structure of the colliding nuclei and nucleon transfer processes represent intrinsic degrees of freedom. They are coupled to the relative ion motion and, in general, increase the probability of tunnelling. The influence of couplings to nucleon transfer channels relatively to inelastic excitations, on heavy-ion fusion cross sections, is one of the still open problems in this field. We present a new analysis of several systems, based on the combined observation of the energy-weighted excitation functions E σ in relation to their first energy derivatives d (E σ) / d E . The relation between d (E σ) / d E and E σ removes the basic differences due to the varying Coulomb barrier when comparing different systems. We show that, depending on the nuclear structure and/or the presence of strong transfer channels, this representation reveals characteristic features below the barrier. The possible presence of cross section oscillations makes this analysis less clear for light- or medium-light systems. [ABSTRACT FROM AUTHOR]

This document is a summary of a collection of contributions on the topic of neutron stars and the physics behind them. The contributions discuss various aspects of neutron stars, including their equation of state, nuclear matter properties, and astrophysical observations. The authors explore different models and theories to understand the behavior and properties of neutron stars. The document also highlights the open problems and challenges in the study of neutron stars, such as determining the maximum and minimum masses, understanding the origin of magnetic fields, and investigating the existence of exotic stars. The authors believe that advancements in experimental methods and astrophysical observations, along with theoretical research, will provide solutions to these open problems in the future. [Extracted from the article]

The nuclear dd-fusion reaction can proceed by three possible channels: , , . Interest in dd-fusion has been aroused by both fundamental research and astrophysics and applied science, particularly in the field of fusion reactor development. In the 1970s, the idea of studying the nuclear dd-fusion reaction using polarized deuteron beams was proposed at the Kurchatov Institute. The development of this idea was continued in the PolFusion (polarized fusion) nuclear physics experiment, which aims at studying the reaction of nuclear dd synthesis with polarized source particles in the low energy region. The experiment is planned to measured the scattering asymmetries of dd-fusion reaction products in the final state at different mutual orientation of the spins of colliding deuterons in the energy range 10–100 keV. The authors present an overview of the status of the experiment. [ABSTRACT FROM AUTHOR]

We study the coupling of hydrodynamics and reactions in simulations of the double-detonation model for Type Ia supernovae. When assessing the convergence of simulations, the focus is usually on spatial resolution; however, the method of coupling the physics together as well as the tolerances used in integrating a reaction network also play an important role. In this paper, we explore how the choices made in both coupling and integrating the reaction portion of a simulation (operator/Strang splitting versus the simplified spectral deferred corrections method we introduced previously) influences the accuracy, efficiency, and nucleosynthesis of simulations of double detonations. We find no need to limit reaction rates or reduce the simulation time step to the reaction timescale. The entire simulation methodology used here is GPU-accelerated and made freely available as part of the Castro simulation code. [ABSTRACT FROM AUTHOR]

Over the last three years, the rates of all the main nuclear reactions involving the destruction and production of 26Al in stars (26Al(n, p)26Mg, 26Al(n, α)23Na, 26Al(p, γ)27Si and 25Mg(p, γ)26Al) have been re-evaluated thanks to new high-precision experimental measurements of their crosssections at energies of astrophysical interest, considerably reducing the uncertainties in the nuclear physics affecting their nucleosynthesis. We computed the nucleosynthetic yields ejected by the explosion of a high-mass star (20 M⊙, Z = 0.0134) using the FRANEC stellar code, considering two explosion energies, 1.2 × 1051 erg and 3 × 1051 erg. We quantify the change in the ejected amount of 26Al and other key species that is predicted when the new rate selection is adopted instead of the reaction rates from the STARLIB nuclear library. Additionally, the ratio of our ejected yields of 26Al to those of 14 other short-lived radionuclides (36Cl, 41Ca, 53Mn, 60Fe, 92Nb, 97Tc, 98Tc, 107Pd, 126Sn, 129I, 36Cs, 146Sm, 182Hf, 205Pb) are compared to early solar system isotopic ratios, inferred from meteorite measurements. The total ejected 26Al yields vary by a factor of ~3 when adopting the new rates or the STARLIB rates. Additionally, the new nuclear reaction rates also impact the predicted abundances of short-lived radionuclides in the early solar system relative to 26Al. However, it is not possible to reproduce all the short-lived radionuclide isotopic ratios with our massive star model alone, unless a second stellar source could be invoked, which must have been active in polluting the pristine solar nebula at a similar time of a core-collapse supernova. [ABSTRACT FROM AUTHOR]